Chickenpox – Symptoms and Causes

Overview

Chickenpox is a highly contagious illness triggered by the varicella-zoster virus. The disease causes an itchy rash with small blisters containing fluid. The virus spreads easily among people who haven’t been infected before or received a vaccination.

Before widespread vaccination began, chickenpox affected many children.

The chickenpox vaccine provides a safe and reliable method to protect children from the uncomfortable symptoms of the illness, potential complications, and spreading the virus to others.

Vaccination has dramatically reduced chickenpox cases in communities where it’s routinely given.

Signs and Symptoms

Chickenpox creates noticeable symptoms that develop in stages. The first signs typically appear 10 to 21 days after exposure to the virus. Most people recover within 5 to 10 days after the rash first appears.

Before the rash develops, you might experience fever, reduced appetite, headache, and fatigue and general discomfort.

The signature chickenpox rash develops through three distinct phases:

1. Initial bumps (papules) – raised spots emerge over several days.
2. Fluid-filled blisters (vesicles) – form within about a day, then break open.
3. Crusting and scabbing – protective crusts form over broken blisters as they heal.

New spots continue to appear for several days, meaning you might have all three stages present at the same time. The rash can spread across the entire body.

Some people develop blisters in the throat, eyes, or mucous membranes lining the urethra, anus, or vagina. A person remains contagious from 48 hours before the rash appears until all broken blisters have fully crusted over.

When to Contact a Healthcare Provider

Call your healthcare provider if you suspect chickenpox. They can usually diagnose it by examining the rash and evaluating other symptoms. Call ahead for appointments to avoid exposing others in waiting areas.

Seek medical attention if:

• The rash spreads to one or both eyes
• Skin around the rash becomes unusually warm, tender, or red (possible bacterial infection)
• You experience serious symptoms alongside the rash, including:
  • Dizziness or confusion
  • Rapid heartbeat
  • Breathing difficulties
  • Muscle coordination problems
  • Worsening cough
  • Vomiting
  • Stiff neck
  • Fever above 102°F (38.9°C)

Also notify your provider if you live with people who haven’t had chickenpox or the vaccine, someone who is pregnant, or individuals with weakened immune systems or those taking immunosuppressive medications.

Your doctor may prescribe antiviral medications to fight the infection or treat complications that might develop from chickenpox.

Causes

Chickenpox develops from the varicella-zoster virus. This highly contagious virus spreads in two main ways:

1. Direct contact – touching the fluid from chickenpox blisters.
2. Airborne transmission – breathing in respiratory droplets when an infected person coughs or sneezes.

The virus enters the body through the respiratory system or through direct contact with the skin.

Risk Factors

People who have not had chickenpox before or haven’t received the chickenpox vaccine face a higher risk of infection. Those working in schools or childcare centers should make vaccination a priority due to frequent exposure to children.

Most individuals with a history of chickenpox or vaccination develop immunity. If you get chickenpox after vaccination, you’ll typically experience milder symptoms, fewer blisters, and little to no fever.

While uncommon, some people may contract chickenpox more than once. This happens rarely but remains possible even with previous exposure or vaccination.

Possible Health Problems

Some people face higher chances of developing serious problems from chickenpox. These include:

• Babies under 1 year old, especially if their mothers never had chickenpox or the vaccine
• Teenagers and adults
• Women who are pregnant without prior chickenpox immunity
• People who smoke
• Individuals with weakened immune systems due to cancer treatments, HIV medications, or organ transplant drugs
• Those with chronic conditions like asthma who take medications that affect immune response

While most people recover from chickenpox without issues, those in these groups should be especially careful about exposure to the virus.

Pregnancy Concerns

Chickenpox during pregnancy can create serious problems. When infection happens early in pregnancy, babies have higher risks of being born with low weight and developing limb abnormalities.

The timing of infection matters greatly. If a mother gets chickenpox just before delivery (within a week) or shortly after giving birth, her baby faces a higher risk of dangerous infections.

If you’re pregnant and not sure if you’ve had chickenpox before, talk with your healthcare provider about testing and protective measures.

Connection to Shingles

After you recover from chickenpox, the virus doesn’t leave your body. Instead, it remains dormant in nerve cells.

Years or decades later, this hidden virus can reactivate as shingles—painful blisters that typically appear in a strip on one side of the body.

Who typically gets shingles?

• Older adults
• People with weakened immune systems

Shingles itself can lead to a painful condition called postherpetic neuralgia, where nerve pain continues long after the blisters heal. This pain can be severe and last for months or even years.

For protection, health experts recommend the Shingrix vaccine for adults 50 and older, and people 19 and older with weakened immune systems.

This recommendation applies even if you’ve already had shingles or received an older shingles vaccine.

Preventing Chickenpox

The chickenpox (varicella) vaccine is the most effective prevention method available. According to health experts, completing the two-dose series provides over 90% protection against chickenpox.

Even if someone gets infected after vaccination, their symptoms are typically much milder than those who haven’t been vaccinated.

In the United States, two vaccine options are available:

• Varivax: Contains only the chickenpox vaccine and is approved for people 1 year and older.
• ProQuad (MMRV): Combines chickenpox with measles, mumps, and rubella vaccines for children ages 1-12.

The standard vaccination schedule includes:

Age Group	Recommended Doses	Timing
12-15 months	First dose	As part of routine childhood vaccines
4-6 years	Second dose	Before starting school
7-12 years (unvaccinated)	Two doses	At least 3 months apart
13+ years (unvaccinated)	Two doses	At least 4 weeks apart

Parents should know that for some children between 12-23 months, the combination MMRV vaccine might slightly increase the risk of fever and seizures.

The vaccine is especially important for people with higher exposure risks, including:

• Healthcare workers
• Teachers
• Childcare employees
• Military personnel
• International travelers
• Adults living with young children
• Women of childbearing age (who aren’t pregnant)

If you’re unsure whether you’ve had chickenpox or been vaccinated, a simple blood test can provide this information.

Important safety considerations:

Certain people should not get the chickenpox vaccine or should wait:

1. Pregnant women should wait until after pregnancy.
2. People planning pregnancy should avoid conception during vaccination and for one month after.
3. Those with weakened immune systems
4. People allergic to gelatin or the antibiotic neomycin
5. Cancer patients receiving radiation or certain medications
6. Those who recently received blood products

Research consistently shows the chickenpox vaccine is both safe and effective. Side effects are usually mild and may include soreness, redness, or swelling at the injection site.

In rare cases, a person might develop a small rash or mild fever after vaccination.

If you have questions about whether the vaccine is right for you or your child, speak with a healthcare provider who can offer personalized guidance based on your specific health situation.